The field of the present invention is saddle-riding type vehicles and the structure and component arrangements therefor.
A saddle-riding type vehicle contemplated for use on rough terrain, particularly of a four-wheel variety, requires a high strength vehicle frame. For example, in Japanese Patent Laid-Open Hei 1-87097, a vehicular frame is disclosed, as illustrated herein in FIG. 1. The vehicular frame 01 includes pairs of right and left front frames 03, lower frames 04, center frames 05, seat rails 06 and the like, rather than a large size main frame 02.
This vehicular frame has a three-block structure. A first block includes front frames 03, lower frames 04, reinforcing frames 07 and the like for supporting a front wheel. A second block includes a main frame 02 and center frames 05 for surrounding an engine. A third block includes seat rails 06 and reinforcing stays 08 for supporting a seat. This structure is intended to enhance the rigidity by each block. However, as to the whole structure, stress concentrations occur which are due to longitudinal external forces at the joints between respective blocks. Accordingly, to enhance the whole structure, it is necessary to further employ reinforcing members. This complicates the frame construction and results in increased weight.
A prior air cleaner apparatus of a saddle-riding type vehicle including a fuel tank ahead of a seat is constructed as shown in Japanese Patent Laid-Open Sho 63-309761. A suction duct extends a substantial distance from an air cleaner to under a seat where it is bent and opened. This long suction duct supplies air to the air cleaner apparatus while preventing the permeation of mud, water and the like. The extended suction duct is disadvantageous because it increases cost and weight and also increases engine output loss.
An exhaust of a conventional saddle-riding type vehicle is constructed as shown in, for example, Japanese Patent Laid-open Sho 62-258112, wherein the connecting portion between the exhaust tube and a muffler is disposed ahead of the rear fenders. In such a system, to remove the muffler for repair, exchange, or maintenance/inspection, the rear fenders must first be removed. This can substantially increase the time needed for muffler removal.
In saddle-riding type vehicles, fuel tanks are generally disposed ahead of the seat, supported on the frame members extending in the longitudinal direction. The front end portion and the rear end portion of such fuel tanks are typically connected to these frame members.
For example, a fuel tank of an auto-bicycle disclosed in Japanese Utility Model Hei 1-109489 is provided ahead of a seat over a main pipe extending from a head pipe. The front end portion thereof is engaged with the stay member for connecting a head pipe, a main pipe and a down tube to each other; and the rear end portion thereof is mounted on a vehicular frame by hooking the upper end of an elastic band onto a projection provided on the rear surface of the fuel tank, and hooking the lower end of the elastic band onto a hook provided on the extension portion of the main pipe.
Also, a fuel tank of an auto-bicycle disclosed in Japanese Utility Model Hei 2-147390 is supported on frame members, wherein the front and rear end portions thereof are mounted on the frame members.
Accordingly, it is necessary to provide tank fixtures on the portions of the frame members adjacent to the fuel tank in front of and behind the fuel tank, respectively. Further, in the case of mounting the fuel tank on a pair of right and left frame members, it is necessary to provide a cross member for connecting the right and left frame members to form the tank fixtures. It is impossible to effectively utilize the spaces in front of and behind the fuel tank as the areas for mounting the other members.
For example, it is impossible to dispose an air cleaner usually provided under a seat very close to the rear end of the fuel tank to effectively utilize the space. In the saddle-riding type vehicle, many components must be disposed in the restricted area around the vehicular frame; and therefore, the effective utilization of space becomes important. The above is not limited to the fuel tank but is extended to the other vessels mounted on the frame members. It is desired to mount these vessels on the frame members for disposing other components as close to the front and rear sides of these vessels as possible.